1. Field of the Invention
The present invention relates to a wiper blade, which includes a lever assembly made by connecting levers in tournament style, and more particularly to a wiper blade suitable for wiping a surface of a vehicle front glass (a windshield), which shows a large change in a curvature of the surface. The present invention further relates to a vehicle wiper system having such a wiper blade.
2. Description of Related Art
In general, a wiper blade for wiping a surface of a vehicle front glass (a windshield) includes a lever assembly, which is made by connecting metal levers in tournament style. The lever assembly holds a wiper strip, to which backing plates are installed. However, such a wiper blade generally does not have good appearance due to exposure of the lever assembly, which includes the metal levers.
To address the above disadvantages, for example, Japanese Unexamined Utility Model Publication No. H07-28759 or H07-26266 discloses a wiper blade, in which levers of a lever assembly are made of synthetic resin and are shaped to have integral appearance after assembly of the levers into the lever assembly to improve appearance of the wiper blade.
However, in the lever assembly disclosed in the above publication, each lever is made of the resin, so that a wall thickness of each lever needs to be disadvantageously increased to achieve a required strength and a required rigidity. This results in an increase in the size of each lever and also an increase in the size of the lever assembly. Thus, the wiper blade disadvantageously becomes larger than the wiper blade having the metal levers.
To address the above disadvantage, it is conceivable to provide a resin cover member to the lever assembly of the wiper blade, which has the metal levers, to improve the appearance. The resin cover receives the lever assembly and extends from one end to the other end of the wiper strip.
However, the ends of the wiper strip are significantly flexed during its wiping operation due to a change in the curvature of the wiping surface of the glass. Particularly, the front glass of the vehicle shows a large change in the curvature at the lateral sides of the front glass. Thus, the ends of the wiper strip, which wipes such a front glass surface, are largely flexed. Thus, when the cover member is simply installed to the lever assembly, a large space could be formed between the ends of the wiper strip and the cover member. Thus, there is still a need for improving the wiper blade.
Furthermore, a fin is integrally formed in each lever recited in Japanese Unexamined Utility Model Publication No. H07-28759 to limit lifting of the wiper blade from the glass surface during traveling of the vehicle. It has been also proposed to install a separately manufactured fin member to the lever assembly of the wiper blade, which includes the metal levers. However, in the fin member, which is formed separately from the lever assembly, legs are provided in a plate-like fin, which is elongated in a longitudinal direction of the wiper strip. The fin member is installed to the lever assembly through the legs. Thus, depending on the installation position of the fin member, the fin member may cause an increase in the size of the wiper blade in a transverse direction or in a vertical direction. Furthermore, the lever assembly is directly exposed and is not made integrally with the fin member. Thus, appearance of the wiper blade is not good.
Furthermore, the fin member, which is recited in Japanese Unexamined Utility Model Publication No. H07-28759, or the fin member, which is formed separately and is installed to the lever assembly, may have a top ridge, which shows a constant amount of offset relative to a center line of the wiper blade. Thus, the effect for limiting the lifting of the wiper blade from the glass surface is not significant.